I am looking to buy a new lens for my Nikon D50 pretty soon and am looking at the 18-200 type lenses which i cannot decide on which one to get the Nikon VR lens is a little out of my budget so I have narrowed it down to

the Sigma 18-200mm F3.5-6.3 DC

-or-

the Quantaray 18-200mm F3.5-6.3 DC

-or-

the Tamron 18-200mm F3.5-6.3 XR DI 2

Those are the ones I am looking at unless I can fond a Nikon VR for under $500 (I know I am dreaming )

Since I am new to the Digital SLR world any and all advice is greatly appreciated!

Here's my take on buying lenses with that much glass in them, my dad was a pro photographer all of his life, he would tell me how a zoom with that much of a zoom range will cost you in optical quality. Now that was back in the mid 80's when the super zooms were starting to come out, I think his argument is still valid today. That's just too much glass in one lens, yes the technology has gotten better but everytime I read a lens test report on one these super zooms they go on to explain how you lose some quality, it's inevitable. If your budget allows, I would split that zoom range up into two good quality lenses, I think you'll be more happy from a qualty and sharpness standpoint.

thanks that makes very much sense and I already have a 28-80mm and a 70-300 mm lens and am very happy with both f them but I am looking for a good combination of the two so I do not have to keep changing back and fourth and this lens seems like the best choice and despite your very valid points I have been able to use the Nikkor VR version of the lenses that I mentioned in my above post and all the images came out looking really nice be the zoom at 10mm 50mm 100m or even 200mm

Quoting Ilikeflight (Reply 2):all the images came out looking really nice be the zoom at 10mm...

I'm really curious how you got those three lenses to produce images at 10mm???

I think you already got good advice, stick with what you have. If I had your lenses and was looking for lens number three, I would save up my pennies and either buy wider (like 12-24mm) for cockpits and landscapes, or better quality long glass (like the 70-200 AFS VR) to improve overall image quality. I wouldn't be looking to overlap another layer of consumer glass on two existing consumer lenses that cover the same range already. The inconvenience of switching lenses would be worth the 'hassle' in exchange for better glass.

I am getting the 70-300 VR for aviation photography (currently using a 70-300 ED without VR) and the 18-200 replaced my 18-70. I must say I am impressed by the quality of the 18-200. I will always have it on my D200 when I don't want to carry around the camera bag. Very flexible.